The major goal of this research project is to examine the physiologic and pharmacologic interactions of cholinergic and adrenergic nervous systems in the eye. The sensitivity of cholinergic and adrenergic effectors in the rabbit eye will be systematically altered, and the resulting changes in ocular response as to pupillary diameter, intraocular pressure, and outflow facility will be determined for the adrenergic agents norepinephrine, epinephrine, and isoproterenol and for the cholinergic agents pilocarpine and carbachol. The influence of stimulus variation on ocular responses will first be determined in rabbits maintained chronically in either continuous light or continuous dark. The effect of surgical denervation produced by removal of either the superior cervical ganglion or the ciliary ganglion will then be examined. The effect of acute and chronic administration of pharmacologic agents reported to produce supersensitivity or subsensitivity of tissues to adrenergic and to cholinergic drugs will finally be explored.